Method for regenerating waste developers used for processing silver halide photographic materials and method for storing developers

ABSTRACT

A method for regenerating a spent developer used for processing silver halide photographic materials which comprises electrolyzing the spent developer using an electrolytic cell including an ion exchange membrane and composed of a cathode compartment and an anode compartment with the anode and the cathode being separated from each other by an anion exchange membrane, while charging the spent developer into the cathode compartment and an electrolytic solution into the anode compartment.

This invention relates to a method for regenerating a waste developerused for processing silver halide photographic materials, and to amethod for storing a developer for use in processing silver halidephotographic materials.

Silver halide black-and-white photographic materials, after exposure forphotographing or printing, are processed by a series of steps includingdevelopment, fixation, rinsing and drying to form a photographic imagethereon. Likewise, after being exposed for photographing or printing,silver halide color photographic materials are processed, in principle,by a process essentially comprising color development, bleaching,fixation, rinsing and drying to form a color photographic image althoughthe method of processing differs somewhat according to the types of thecolor photographic materials. Since wastes of the developer, bleachingsolution and fixer used for processing these photographic materialscontain noxious substances, they have to be discarded after beingtreated by some method to render them non-noxious, or be re-used afterbeing subjected to some regeneration treatment, thus confining thewastes within the processing system.

Various methods of regeneration have been proposed to date for treatingthe used developer, bleaching solution and fixer.

Generally, the developer for silver halide photographic materials is anaqueous solution containing a developing agent, a preservative, anaccelerator and an inhibitor. When the developing agent reacts with theexposed silver bromide or silver iodide in the emulsion layer of thephotographic material, a silver image precipitates in the emulsionlayer, and the oxidized developing agent and bromine or iodine ions areformed as by-products in the developer. In the case of the colordevelopment of a color photographic material, the oxidized developingagent combines with the color coupler in the emulsion layer to form adye image. However, since the color developing agent and thepreservative are susceptible to air oxidation, both black-and-whitedevelopers and color developers, after being spent, contain the oxidizeddeveloping agent, the oxidized preservative and bromine or iodine ions(inhibitor) built up therein.

In order to regenerate the spent developer, a method has previously beensuggested in which the spent developer is passed through an ion-exchangeresin to remove the bromine or iodine ions (John H. Priesthoff and JohnG. Stott, Journal of the SMPTE, Vol. 65, pages 478 to 484, 1956). Thismethod is certainly effective for removing bromine or iodine ions, butis insufficient for removing the oxidized developing agent. For example,a black-and-white developer has the defect that the developing agentsuch as hydroquinone adsorbs to the ion-exchange resin. Furthermore,when the bromine or iodine ions adsorb to the ion exchange resin tosaturation, an additional step of regenerating the resin is required,and the method lacks simplicity.

Another method for regenerating the waste developer has been suggestedin which the waste developer is electrodialyzed using an electrodialyticcell including an ion exchange membrane and composed of a cathodecompartment, a plurality of deionation compartments (in which a cationexchange membrane is disposed on the cathode side and an anion exchangemembrane on the anode side), a plurality of enionation compartments (inwhich an anion exchange membrane is disposed on the cathode side, and acation exchange membrane on the anode side), and an anode compartmentwith the cathode and the anode being separated from each other by anumber of anion exchange membranes and cation exchange membranesarranged alternately, while charging the waste developer into thedeionation compartments and a solution of sodium sulfate into theenionation compartments, and passing a direct current between thecathode and the anode, thereby to remove bromine or iodine ions built upin the waste developer. (S. Mizusawa, A. Sasai and N. Mii, Bulletin ofthe Society of Scientific Photography of Japan, No. 18, 38-44, 1968).This method makes it possible to remove bromine or iodine ionsaccumulated in the waste developer, but the oxidized developing agentand the oxidized preservative cannot be eliminated, thus leading to anincomplete regeneration of the developer.

After the color development, the emulsion layers of a color photographicmaterial contain a silver image and a dye image conjointly, and unlessthe silver image is removed, a clear dye image cannot be completelyformed. The bleaching treatment is an operation whereby this silverimage is converted to silver bromide which is soluble in the fixer.

When the silver image is treated with a bleaching solution comprisingpotassium ferricyanide and potassium bromide, the silver image becomessilver bromide in the emulsion, and potassium ferrocyanide is formed asa by-product in the bleaching solution. When hydrobromic acid and ozoneare caused to act on the spent bleaching solution, the potassiumferrocyanide is oxidized to potassium ferricyanide, and potassiumbromide is formed as a by-product, thus making it possible to reuse thebleaching solution. (T. W. Baker and T. J. Dagon, Image Technology,13-25, June/July; 19-24, August/September, 1972)

When the above spent bleaching solution is oxidized by addition ofpotassium persulfate, the potassium ferrocyanide becomes potassiumferricyanide, thus making it possible to reuse the bleaching solution.(B. A. Huchins and L. E. West, Journal of the SMPTE, 66, 764, 1967)

The emulsion layer of a black-and-white photographic material afterprocessing with a developer and the emulsion layer of a colorphotographic material after treatment with a bleaching solution bothcontain silver bromide or silver iodide remaining therein. The fixationis an operation whereby the silver bromide and silver iodide aredissolved and removed from the emulsion.

When the above silver bromide or silver iodide is treated with a fixerconsisting mainly of sodium thiosulfate or ammonium thiosulfate, itchanges to a silver thiosulfate complex salt, and is removed from theemulsion. On the other hand, the silver thiosulfate complex salt andbromine or iodine ions build up in the fixing bath.

When the spent fixing solution is electrolyzed in an electrolytic cellcomprising a stainless steel cathode and a graphite anode, the silverions dissociated from the silver thiosulfate complex salt is reduced atthe cathode to precipitate metallic silver. The bromine or iodine ionsare removed by secondary discharge at the anode. Hence, the fixingsolution can be reused. This method of electrolytic regeneration of thespent fixing solution makes it possible to reuse the fixer andsimultaneously recover silver, and has heretofore been used with goodresults in large developing laboratories. (R. P. Gyori and F. J. Scobey,Journal of the SMPTE, 81, 603-606, 1972)

The Japanese-language periodical "Motion Picture and TelevisionTechnology", No. 254, 34-40, October 1973 discloses a method forregenerating wastes of a bleaching solution and fixing solutionsimultaneously. This method involves the electrolysis of the waste fixerin a cathode compartment and the waste bleaching solution containingpotassium ferricyanide in an anode compartment using an electrolyticcell in which a stainless steel cathode is separated from a graphiteanode by means of an anion exchange membrane. According to thiselectrolytic method, the silver ions dissociated from the silverthiosulfate complex salt are reduced at the cathode to precipitatemetallic silver. At the anode, ferrocyanide ions are oxidized toferricyanide ions. Bromine ions in the catholyte solution migrate to theanode compartment through the anion exchange membrane, and therefore,the removal of the bromine ions in the waste fixing solution and thesupply of bromine ions to the waste bleaching solution can be performedat the same time, thus resulting in the simultaneous regeneration of thewaste fixing solution and the waste bleaching solution. This method ofregeneration takes good advantage of a reducing reaction of silver ionsat the cathode and an oxidation reaction of ferrocyanide ions at theanode, which are known reactions in the field of inorganicelectrochemistry.

As described above, many developing laboratories are actually re-usingthe waste bleaching solution and fixing solution, but no satisfactorymethod for regenerating waste developers has been provided up to date.

It is an object of this invention therefore to provide a method forregenerating waste developers used for processing silver halideblack-and-white or color photographic materials.

Another object of this invention is to provide a method for preventingwater pollution in rivers and seas to be caused by the discharge ofwaste developers used for processing silver halide photographicmaterial.

Still another object of this invention is to provide a method forpreventing the oxidation of developers which are susceptible to airoxidation.

SUMMARY OF THE INVENTION

This invention embrances the following embodiments.

(1) A method for regenerating waste developers used for processingsilver halide photographic materials which comprises electrolyzing thewaste developer using an electrolytic cell including an ion exchangemembrane and composed of a cathode compartment and an anode compartmentwith the cathode and the anode being separated from each other by ananion exchange membrane, while charging the waste developer into thecathode compartment and an electrolyte solution into the anodecompartment.

(2) A method for regenerating waste developers used for processingsilver halide photographic materials, which comprises electrolyzing thewaste developer using an electrodialytic cell including an ion exchangemembrane and composed of a cathode compartment, a plurality ofenionation compartments, a plurality of deionation compartments and ananode compartment with the cathode and the anode being separated fromeach other by an anion exchange membrane, while charging the wastedeveloper into the cathode compartment and the effluent from the cathodecompartment into the deionation compartments.

(3) A method for regenerating developers used for processing silverhalide photographic materials, which comprises using an electrolyticcell including an ion exchange membrane and composed of a cathodecompartment and an anode compartment with the cathode and the anodebeing separated from each other by an anion exchange membrane, and anelectrodialytic cell including an ion exchange membrane and composed ofa cathode compartment, a plurality of enionation compartments, aplurality of deionation compartments and an anode compartment with thecathode and the anode being separated from each other by anion exchangemembranes and cathon exchange membranes arranged alternately, andcharging the waste developer into the cathode chamber of theelectrolytic cell to electrolyze it and then charging the effluent fromthe cathode compartment into the deionation compartments of theelectrodialytic cell to electrodialyze it.

(4) An apparatus for regenerating waste developers used for processingsilver halide photographic materials, comprising an electrolytic cellincluding an ion exchange membrane and composed of a cathode compartmentand an anode compartment with the cathode and the anode being separatedfrom each other by an anion exchange membrane, and an electrodialyticcell including an ion exchange membrane and composed of a cathodecompartment, a plurality of enionation compartments, a plurality ofdeionation compartments and an anode compartment wit the cathode and theanode being separated from each other by anion exchange membranes andcation exchange membranes arranged alternately, said cells beingconnected to each other by piping.

(5) A method for regenerating waste developers used for processingsilver halide photographic materials, which comprises using anelectrolytic cell including an ion exchange membrane and composed of acathode compartment and an anode compartment with the cathode and theanode being separated from each other by a cation exchange membrane, andan electrodialytic cell including an ion exchange membrane and composedof a cathode, a plurality of enionation compartments, a plurality ofdeionation compartments and an anode compartment with the cathode andthe anode being separated from each other by anion exchange membranesand cation exchange membranes arranged alternately, and charging thewaste developer into the cathode compartment of the electrolytic cell toelectrolyze it, and then charg ng the effluent from the cathodecompartment into the deionation compartments of the electrodialysis cellto electrodialyze it.

(6) An apparatus for regenerating waste developers used for processingsilver halide photographic materials, comprising an ion exchangeelectrolytic cell including an ion exchange membrane and composed of acathode compartment an an anode compartment with the cathode and theanode being separated from each other by a cation exchange membrane andan electrodialytic cell including an ion exchange membrane and composedof a cathode, a plurality of enionation compartments, a plurality ofdeionation compartments and an anode compartment with the cathode andthe anode being separated from each other by an anion exchange membraneand a cation exchange membrane, said cells being connected to each otherby piping.

(7) A method for treating discharge liquids during the regeneration ofwaste developers for silver halide photographic materials, whichcomprises treating an effluent from an anode compartment of anelectrolytic cell including an ion exchange membrane and composed of acathode compartment and the anode compartment with the cathode and theanode being separated from each other by an anion exchange membrane anda discharge liquid from enionation compartments and an anode compartmentof an electrodialytic cell including an ion exchange membrane andcomposed of a cathode, a plurality of the enionation compartments, aplurality of deionation compartments and the anode compartment with thecathode and the anode being separated from each other by anion exchangemembranes and cation exchange membranes arranged alternately, withchlorine or a hypochlorite.

(8) A method for storing a developer for silver halide photographicmaterials, which comprises charging a solution of an acid into an anodeof an electrolytic cell including an ion exchange membrane and composedof a cathode compartment and the anode compartment with the cathode andthe anode being separated from each other by a cation exchange membrane,and the developer into the cathode compartment, and passing a directcurrent between the cathode and the anode.

(9) An apparatus for storing a developer for silver halide photographicmaterials, comprising an electrolytic cell including a cathode, an anodeand a cation exchange membrane, the cation exchange membranepartitioning the electrolytic cell into an anode compartment and acathode compartment, the anode compartment containing an anode and thecathode compartment containing a cathode; and means for passing a directelectric current between the cathode and the anode.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an electrolytic cell including an ionexchange membrane which is suitable for the performance of the presentinvention; and

FIG. 2 is a schematic view of an electrodialytic cell including anion-exchange membrane suitable for the performance of the presentinvention. In the drawings, the arrows show the directions in which thesolution flows.

DETAILED DESCRIPTION OF THE INVENTION

The various embodiments of this invention will be described below withreference to the accompanying drawings.

The process of regenerating a waste developer used for processing silverhalide photographic materials in accordance with the embodiment (1) ofthis invention is shown in FIG. 1. Referring to FIG. 1, an electrolyticcell 1 including an ion exchange membrane is divided into a cathodecompartment 5 and anode compartments 6 by separating a cathode 2 fromanodes 3 by means of anion exchange membranes 4. The waste developerused for processing silver halide photographic materials is charged froma supply line 7 into the cathode compartment, and an electrolyticsolution is charged into the anode compartments 6 from another supplyline 8. The waste developer is electrolyzed by passing a direct currentbetween the cathode 2 and the anodes 3. The developer recovered by theelectrolysis flows out from an effluent line 9. The electrolyticsolution flows out from another effluent line 10.

The cathode 2 is made of, for example, iron, nickel, lead, zinc, orstainless steel, and the anodes 3 are made of, for example, graphite,platinum, platinum-plated titanium, lead, or magnetite. Desirably, theanion exchange membranes 4 are of a strong base type anion exchangemembrane. Examples of the electrolyte solution to be filled in the anodecompartments 6 of the electrolytic cell 1 are an aqueous solution of analkali such as sodium hydroxide or potassium hydroxide, an aqueoussolution of a salt such as sodium sulfate or potassium sulfate, and anaqueous solution of an acid such as sulfuric acid. Preferably, theconcentration of the electrolyte solution is generally 0.1 N. There isno particular upper limit to the concentration, but concentrations ofnot more than 1 N are sufficient.

The waste developer used for processing silver halide photographicmaterials is filled in the cathode compartment 5. The developing agentin the developer is a chemical which reduces only the latent image areaof silver bromide or silver iodide in the emulsion layer but not therest. Black-and-white developers contain such a developing agent ashydroquinone, methyl p-aminophenol sulfate salt, or1-phenyl-3-pyrazolidone. Examples of the color developing agent in colordevelopers include N,N-dialkyl-p-phenylenediamine-type compounds, suchas diethyl p-phenylenediamine sulfate, hydroxyethyl ethylp-phenylenediamine sulfate, 2-amino-5-diethyl aminotoluenehydrochloride, 4-amino-N-ethyl-N-(β-methanesulfonamideethyl)-m-toluidine sesquisulfate monohydrate, or4-amino-N-hydroxyethyl-N-ethyl-m-toluidine sulfate.

The preservative in the developer is a chemical added in order toprevent the oxidation of the developing agent, and includes, forexample, potassium sulfite, sodium sulfite, and sodium metabisulfite.The accelerator in the developer is a chemical which strengthens thereducing action of the developing agent, and includes, for example,alkalies such as sodium hydroxide or potassium hydroxide, and alkalinesalts such as sodium carbonate, potassium carbonate, borax, or sodiummetaborate. The inhibitor in the developer is a chemical which stronglyinhibits the development of those areas of the photographic materialwhich have been exposed insufficiently, and removes fog. Examples of theinhibitor are potassium bromide, sodium bromide, potassium iodide, andsodium iodide.

When the developing agent in the developer reacts with the exposedsilver bromide or silver iodide of the emulsion layer, a silver imageprecipitates in the emulsion layer, and the oxidized developer agent,hydrogen ions and bromine or iodine ions are formed as by-products inthe developer. The hydrogen ions disappear as a result of beingneutralized with the accelerator in the developer. In the case of colordevelopment, the oxidized developing agent combines with a color couplerin the emulsion layer to form a dye image, and in the case ofblack-and-white development, it becomes one component of the wastedeveloper. On the other hand, the developing agent, whether for colordevelopment or black-and-white development, is susceptible to airoxidation, and the preservative is likewise susceptible to airoxidation. Consequently, the oxidized developing agent, the oxidizedpreservative and bromine or iodine ions build up in the waste developer.

More specifically stated, when a black-and-white developing agent suchas hydroquinone is oxidized, it changes to a quinone-type compound suchas benzoquinone, and a part of it reacts with a sulfite present as thepreservative to form a sulfone compound such as hydroquinonemonosulfonate. Both of these compounds are accumulated in the wastedeveloper. On the other hand, when a color developing agent such as anN,N-dialkyl-p-phenylenediamine compound undergoes air oxidation in thedeveloper, it forms an azo dye-type compound and a quinone diiminecompound. Part of the quinone diimine-type compound reacts with thesulfite preservative to form a sulfone compound such as anN,N-dialkyl-p-phenylenediamine monosulfonate. Both of these compoundsare accumulated in the waste developer.

The type of the oxidized preservative differs of course according to thetype of the preservative, but when sodium sulfite is used as thepreservative, sodium sulfate is formed as the by-product oxidationproduct.

When the waste development used for processing silver halidephotographic materials and having the abovementioned composition ischarged into the cathode compartment 5 of the electrolytic cell 1 shownin FIG. 1 and a direct current is passed between the cathode 2 and theanodes 3, bromine or iodine ions in the waste developer migrate to theanode compartments 6 through the anion exchange membranes 4 and is thusremoved. The oxidation product of the black-and-white developing agent,such as benzoquinone, and the oxidation product of the preservative,such as sodium sulfate, are reduced by a cathodic reaction, and revivedrespectively to the black-and-white developing agent and thepreservative. The quinone diimine-type compound and the azo dye-typecompound as the oxidation products of the color developing agent arereduced by a cathodic reaction, and thus revived to the color developingagent. The sulfonated product of the black-and-white developing agent,such as hydroquinone monosulfonate, and the sulfonated product of thecolor developing agent, such as an N,N-dialkyl-p-phenylenediaminemonosulfonate, are revived respectively to the black-and-whitedeveloping agent and the color developing agent as a result of thesulfone group bonded to the benzene nucleus being replaced by stronghydrogen generated from the cathode. A part of each of the sulfonatedproducts of the black-and-white developing agent and the colordeveloping agent is dissociated to a sulfone anion-type compound of theblack-and-white developing agent or the color developing agent, andmigrates to the anode compartments 6 through the anion exchangemembranes 4 and is thus removed.

Thus, the method of this invention in accordance with the embodiment (1)makes it possible to remove the oxidized developing agent, the oxidizedpreservative and bromine or iodine ions accumulated in the wastedeveloper, and consequently, to re-use the revivied developer.

The process of regenerating the waste developer used for processingsilver halide photographic materials by the method of this invention inaccoreance with the embodiment (2) is shown in FIG. 2. Referring to FIG.2, the reference numeral 11 represents an electrodialytic cell with anion exchange membrane; 12, a cathode; 13, anodes; 14, anion exchangemembranes; 15, a cation exchange membrane; 16, a cathode compartment;17, anode compartments; 18, deionation compartments (in which the cationexchange membrane is disposed on the cathode side, and the anionexchange membrane on the anode side); 19, an enionation compartment (inwhich the anion exchange membrane is disposed on the cathode side, andthe cation exchange membrane on the anode side); 20, a line forsupplying the solution to the cathode compartment; 21, a line forsupplying the solution to the anode compartment; 22, a line forsupplying the solution to the deionation compartment; 23, a line forsupplying the solution to the deionation compartments; 24, a line forflowing out the solution from the cathode compartment; 25, a line forflowing out the solution from the anode compartment; 26, a line forflowing out the solution from the deionation compartment; and 27, a linefor flowing out the solution from the enionation compartment.

The cathode 12 is made of, for example, iron, nickel, lead, zinc, orstainless steel, and the anode 13 is made of, for example, graphite,platinum, platnium-plated titanium, lead, or magnetite. Preferably, theanion exchange membranes 14 are of a strong base type anion exchangemembrane, and the cation exchange membranes 15 are of a strong acid typecation exchange membrane. An aqueous solution of an alkali such assodium hydroxide or potassium hydroxide, an aqueous solution of a saltsuch as sodium sulfate or potassium sulfate, or an aqueous solution ofan acid such as sulfuric acid is charged into the anode compartment 17and the enionation compartments 19. Preferably, the concentration of theelectrolyte solution is generally 0.1 N. There is no particular upperlimit to the concentration, and concentrations of not more than 1N areusually sufficient. The waste developer used for processing silverhalide photographic materials is charged into the cathode compartment16. The effluent from the cathode compartment 16 is charged into thedeionation compartments 18. As shown in FIG. 2, the effluent from thecathode compartment 16 may be supplied to the deionation compartments 18arranged in parallel to each other or in series through pipelines. Thecathode compartment 16, the deionation compartments 18, the enionationcompartments 19, and the anode compartment 17 need to be insulated sothat no electric current flows among them.

When the waste developer used for processing silver halide photographicmaterials is charged into the cathode compartment 16 of theelectrodialytic cell 11 shown in FIG. 2 and an electric current isflowed between the cathode 12 and the anode 13, the oxidizedblack-and-white developing agent, such as benzoquinone, and the oxidizedpreservative such as sodium sulfate are reduced by a cathodic reaction,and revived to the black-and-white developing agent and thepreservative, respectively. Of the oxidized products of the colordeveloping agent, the quinone diimine-type compound and the azo dye-typecompound are reduced by a cathodic reaction, and revived to the colordeveloping agent. The sulfonated black-and-white developing agent suchas hydroquinone monosulfonate and the sulfonated color developing agentsuch as an N,N-dialkyl-p-phenylenediamine monosulfonate are revived tothe black-and-white developing agent and the color developing agent as aresult of the sulfone group bonded to the benzene nucleus being replacedby strong hydrogen generated from the cathode. When the cathodecompartment 16 is separated from the anion exchange membranes 14,bromine or iodine ions and the sulfone anion-type compound of thedeveloping agent dissociated from the sulfonated product of theblack-and-white or color developing agent migrate to the enionationcompartments 19 through the anion exchange membrane 14. Furthermore, acation (for example, a sodium ion) in the solution in the deionationcompartment migrates to the enionation compartments 19 through thecation exchange membrane 15 and is thus removed. As a result, theconcentrations of bromine or iodine ions, the anion-type compound andcation, etc. in the deionation compartments 18 are decreased (namely,deionation occurs), and the concentrations of these ions increase in theenionation compartments (namely, enionation occurs).

When the cathode compartment 16 is separated by means of the ionexchange membranes 14 as in the electrodialytic cell 11 shown in FIG. 2,the waste developer can be regenerated merely by charging it into thecathode compartment 16. However, when the waste developer is chargedinto one cathode compartment and a plurality of deionation compartmentsin accordance with the method of embodiment (2), a great amount of itcan be regenerated at a low installation cost. Generally, the rate ofreduction of the oxidized developing agent and the oxidized preservativeis faster than the rate of removing bromine or iodine ions and theaniontype compound, but according to this method of the presentinvention, the rate of reduction and the rate of removal may beequilibrated.

In the performance of the embodiment (2) of the present invention, thewaste developer is first charged into the cathode compartment 16 and thedeionation compartments 18, and an electrolyte solution is charged intothe anode compartment 17 and the enionation compartments 19 toelectrolyze the waste developer. When the electrolysis has proceeded toa certain extent and the oxidation product present in the developer isreduced to some extent, the effluent from the cathode compartment 16 ischarged into the deionation compartments 18. The effluent 26 derivedfrom the waste developer originally charged into the deionationcompartments 18 is charged into the cathode compartment 16.

The waste developer can be regenerated even by first charging it intothe deionation compartments 18, and then charging the effluent 26 fromthe deionation compartments 18 into the cathode compartment 16. Itshould be understood that this modified method also lies within thescope of this invention.

According to the method of embodiment (3), the waste developer isregenerated by charging it into the cathode compartment 5 of theelectrolytic cell shown in FIG. 1, electrolyzing it while pouring theelectrolyte solution into the anode compartments 6, and then chargingthe effluent 9 from the cathode compartment 5 into the deionationcompartments 18 of the electrodialytic cell 11 shown in FIG. 2 toelectrodialyze it. At this time, the above-mentioned electrolytesolution is charged into the cathode compartment 16, the enionationcompartments 19 and the anode compartment 17 of the electrodialytic cell11. Preferably, the concentration of the electrolyte solution is about0.1 N. There is no particular upper limit to it, but concentrations ofnot more than 1 N are usually sufficient.

The oxidized developing agent and the oxidized preservative in the wastedeveloper are reduced in the cathode compartment 5, and bromine oriodine ions and a part of the anion-type compound migrate to the anodecompartment 6 through the anion exchange membrane 4 and are thusremoved. When the effluent 9 from the cathode compartment 5 is chargedinto the deionation compartments 18 and electrodialyzed, the bromine oriodine ions and the anion-type compound remaining in the effluent 9migrate to the enionation compartments 19 through the anion exchangemembrane 14. Thus, the components accumulated in the waste developer areremoved to revive the developer.

The method of embodiment (3) also has the advantage that the rate ofreducing the oxidized developing agent and the oxidized preservative canbe equilibrated with the rate of removing the bromine or iodine ions andthe anion-type compound at the anion exchange membrane, and a greatquantity of the waste developer can be regenerated at a low installationcost.

The waste developer can also be regenerated by first charging it ontothe deionation compartments 18 to electrodialyze it, and then chargingthe effluent 26 from the deionation compartments 18 into the cathodecompartment 5 to electrolyze it. It should be understood that thismodified method is also included within the scope of this invention.

The apparatus in accordance with the embodiment (4) of this invention isconstructed by connecting the electrolytic cell shown in FIG. 1 to theelectrodialytic cell shown in FIG. 2 by suitable pipelines so that theliquid to be treated, that is, the electrolytic solution or dialyticsolution, may flow into the electrodialytic cell or the electrolyticcell. The waste developer used for processing silver halide photographicmaterials can be easily regenerated by performing the method of theembodiment (3) using this apparatus.

According to the method of embodiment (5) of this invention, the wastedeveloper can be regenerated by charging it into a cathode compartmentof an electrolytic cell composed of the cathode compartment and an anodecompartment with the cathode and the anode being separated from eachother by a cation exchange membrane (the same electrolytic cell as shownin FIG. 1 except that the cation exchange membrane is used instead ofthe anion exchange membranes 4) and electrolyzing it while charging theelectrolyte solution into the anode, then charging the effluent from thecathode into the deionation compartments 18 of the electrodialytic cell11 shown in FIG. 2 to electrodialyze it. At this time, the electrolytesolution is charged into the cathode compartment 16, the enionationcompartments 19 and the anode compartment 17.

In the cathode compartment of the above electrolytic cell in which thecathode is separated from the anode by the cation exchange mebrane, theoxidized developing agent and the oxidized preservative in the wastedeveloper are reduced. When the effluent from the cathode compartment ispoured into the deionation compartments 18 of the electrodialytic cellshown in FIG. 2 and electrodialyzed, bromine or iodine ions and theanion-type compound in the effluent migrate into the anode compartments19 through the anion exchange membranes 14. Thus, the componentsaccumulated in the waste developer are removed to revive the developer.

The method of the embodiment (5), like the methods of the embodiments(2) and (3), has the advantage that the rate of reducing the oxidizeddeveloping agent and the oxidized preservative can be equilibrated withthe rate of removing the bromine or iodine ions and the anion-typecompound, and a large quantity of the waste developer can be regeneratedat a small installation cost.

The apparatus in accordance with the embodiment (6) of this invention isconstructed by connecting an electrolytic cell with an ion exchangemembrane composed of a cathode compartment and an anode compartment withthe cathode and the anode being separated from each other by a cationexchange membrane (the same electrolytic cell as shown in FIG. 1 exceptthat the cation exchange membrane is used instead of the anion exchangemembranes 4) to the electrodialytic cell shown in FIG. 2 by suitablepipelines so that the liquid to be processed, that is, the electrolyticsolution or the electrodialytic solution, may flow into theelectrodialytic cell or the electrodialytic cell. The waste developerused for processing silver halide photographic materials can be easilyregenerated by performing the method of the embodiment (5) using thisapparatus.

In the electrolysis or electrodialysis in accordance with the methods ofthe embodiments (1), (2) and (5) described above, hydrogen gas evolvesfrom the cathode and the pH of the catholyte solution increases.Furthermore, oxygen gas evolves from the anode, and the pH of theanolyte solution decreases. Accordingly, an acid or alkali may be addedto the catholyte or anolyte solution to maintain the pH of the catholyteor anolyte solution constant.

In the above electrolysis or electrodialysis, the current density of theanion exchange membrane or cation exchange membrane depends upon theconcentration of bromine ions. When the concentration of bromine ions isabout 0.02 gram equivalent/liter, the desirable current density is 2 to10 mA/cm².

The developer revived by the methods of the embodiments (1), (2), (3)and (5) of this invention is re-used either as such or afterreplenishing it with wanted components so that its composition becomesthe same as that of the original developer. If desired, the hydrogen ionconcentration of the revived developer is adjusted by using an alkalineaccelerator or sulfuric acid. In particular, in the regeneration of awaste black-and-white developer, a part of hydroquinone as a developingagent migrates into the anode compartment or deionation compartmentsthrough an anion exchange membrane. Accordingly, this loss needs to bemade up for. In the case of regenerating a waste color developer usedfor processing color photographic materials, the revived developer mustbe replenished corresponding to the amount of the developing agentcoupled with the coupler of the photographic material and the amount ofthe developing agent which has passed through the anion exchangemembrane as a sulfonated anion-type compound.

In short, the methods in accordance with the embodiments (1), (2), (3)and (5 ) of this invention are a method for regenerating the wastedeveloper used for processing silver halide photographic materials byutilizing, either simultaneously or separately, an expedient of reducingoxidation products of the developing agent and the preservativeaccumulated in the waste developer by an electrochemical cathodicreaction, and an expedient of removing bromine or iodine ions and asulfonated anion-type compound derived from the developing agentelectrodialytically by means of an anion exchange membrane.

According to these methods, a revivied developer decolorized to the samecolor as the original developer can be obtaind as a result of thereduction of the oxidation products of the developing agent in the wastedeveloper, and chemicals for formulating the developer can be markedlysaved, and moreover, the waste developer can be reused. Accordingly,water pollution in rivers and seas caused by the waste developer can beeliminated.

One of the above-described known methods which comprises using anelectrodialytic cell with an ion exchange membrane composed of a cathodecompartment, a plurality of deionation compartments, a plurality ofenionation compartments and an anode compartment with the cathode andthe anode being separated from each other by a number of anion exchangemembranes and cation exchange membranes arranged alternately, chargingthe waste developer into the deionation compartments and an aqueoussolution of sodium sulfate into the enionation compartments, andelectrodialyzing the waste developer by passing a direct current betweenthe cathode and the anode is not acceptable for practical purposesbecause it cannot remove the oxidation products of the developing agentand the preservative although it can remove bromine and iodine ions inthe waste developer. In contrast, the methods of this inventiondescribed above can remove not only bromine or iodine ions but also theoxidation products of the color developing agent and the preservative,and therefore, can regenerate the waste developer on a commercial basis.

When the waste developer is regenerated by the methods of theembodiments (1), (2), (3) and (5) of this invention, the electrolytesolution discharged from the anode compartments 6 of the electrolyticcell 1 or from the enionation compartments 19 and the anode compartment17 has a COD (chemical oxygen demand) of about 200 to 20 ppm. This isbecause a part of the developing agent component in the waste developeror the sulfonated anion-type organic compound derived from thedeveloping agent migrates to the anode compartment or enionationcompartments through the anion exchange membrane. Although the COD ofabout 200 to 20 ppm in the effluent from the anode compartment and theeffluent from the enionation compartments is low as compared with theCOD of 30,000 to 3,000 ppm in the waste developer, some treatment toreduce it is required. By treating the effluent from the anodecompartment and the effluent from the enionation compartments withchlorine or a hypochlorite in accordance with the method of embodiment(7), the COD can be drastically reduced. This method is quite unexpectedin view of the fact that treatment of the waste developer with chlorineor a hypochlorite does not so much reduce COD. Chlorine gas or chlorinewater can be used as the chlorine used in this method. Examples of thehypochlorite are sodium hypochlorite, potassium hypochlorite and calciumhypochlorite in the form of a solution or slurry. The sufficient amountof chlorine or the hypochlorite is about 5 g, calculated as availablechlorine, per gram of COD of the effluent from the anode or theenionation compartments. Thus, according to this method, environmentalpollution by the waste developer is completely eliminated.

In spite of the fact that the developer contains a preservative, thedeveloping agent is susceptible to air oxidation during storage, andtherefore, its developing action is reduced. This tendency is especiallyremarkable with color developers containing a preservative in a lowconcentration.

The oxidation of the developing agent and the preservative can beprevented and the pH of the developer can be maintained constant byfilling the developer in a cathode compartment of an electrolytic cellwith an ion exchange membrane composed of the cathode compartment and ananode compartment with the cathode and the anode being separated fromeach other by a cation exchange membrane, and a solution of an acid inthe anode, and passing a direct current between the cathode and theanode.

Suitably, in the method of the embodiment (8), the same cathode andanode as in the case of the electrolytic cell with an ion exchangemembrane are used, and a strong acid type cation exchange membrane isused as the cation exchange membrane. Preferably, cation exchangemembranes having a low electric resistance whose performance is notreduced by being immersed in the developing agent or acids are chosen.The acid to fill the anode compartment is, for example, a solution ofsulfuric acid, phosphoric acid, nitric acid, boric acid, or acetic acid.The concentration of the acid in the solution is 0.1N or more. There isno particular limit, but for commercial operations, concentrations inthe range of 0.1 to 1N are used. In the performance of this method, thesufficient strength of the current (direct current) is 0.5 to 10 mA per10 liters of the developer to be stored. Preferably, the current densityof the cation exchange membrane is 1 to 30 mA/cm², and the currentdensity of the cathode and the anode is 10 to 100 mA/cm².

When a solution of an acid is filled in the anode compartment of anelectrolytic cell including an ion exchange membrane and the developerin the cathode compartment, and a direct current is passed between theanode and the cathode in accordance with the method of the embodiment(8), oxygen gas and a hydrogen ion are generated at the anode. Thehydrogen ion migrates from the anode compartment to the cathodecompartment through the cation exchange membrane to carry electricity.At the cathode, hydrogen gas and a hydroxyl ion are generated. Since thehydroxyl ion is neutralized by the hydrogen ion which has migratedthrough the cation exchange membrane, the pH of the catholyte solution(developer) can be maintained constant. Furthermore, because thedeveloping agent and the preservative are prevented from oxidation by acathodic reaction, their concentrations can be maintained constantduring storage. The concentrations of the accelerator (hydroxyl ion) andthe inhibitor (bromine or iodine ions) can also be maintained alwaysconstant because they cannot permeate through the cation exchangemembrane.

When the method of the embodiment (8) is applied to the storage of adeveloper for silver halide photographic materials, it can be stored forlong periods of time without degeneration. By applying this method to adeveloper being used, it can be stored for long periods of time withoutchanges in its properties.

The apparatus in accordance with the embodiment (9) is suitable forperforming the method of the embodiment (8). It is partitioned into ananode compartment and a cathode compartment by a cation exchangemembrane so that a solution of an acid is charged into the anodecompartment and the developer, into the cathode compartment, and anelectric current can be passed between the anode and the cathode. As oneexample of application, this apparatus also embraces an apparatus forstoring developers in which a solution of an acid is filled in areceptacle for an anode compartment composed of a cation exchangemembrane with its top surface being opened, and the receptacle isimmersed in a developer storage tank (or a developer bath of aprocessor), and an electric current is passed between an anode providedin the above receptacle and a cathode immersed in the developer storagetank but connected to the receptacle.

The above-described embodiments (1) to (9) of this invention can be usedfor regenerating or storing wastes of both black-and-white and colordevelopers.

The following Examples illustrate the present invention morespecifically.

EXAMPLE 1

A black-and-white silver halide photographic film was developed using adeveloper having the composition shown in column A in Table 1. The wastedeveloper (column B) was filled in cathode compartment 5 of anelectrolytic cell with an ion exchange membrane of the type as shown inFIG. 1 in which a lead cathode was separated from a graphite anode by astrong base type anion exchange membrane having permselectivity formonovalent anions. A 0.5N aqueous solution of sodium sulfate was filledin anode compartments 6. Electrolysis was performed while maintainingthe current density of the ion exchange membrane at 8 mA/cm². Afterelectrolyzing for 3 hours, the composition of the waste developer Bchanged to that shown in column C in Table 1. Hydroquinone,1-phenyl-3-pyrazolidone, anhydrous sodium sulfite, borax and sulfuricacid (for pH adjustment) were added to the electrolyzed developer C toform a revived developer having the composition shown in column D inTable 1. Using the revived developer, a black-and-white photographicfilm was developed under the same conditions as in the case of thedeveloper A, the photographic characteristics of the developed imagewere the same as in the case of the developer A.

                  Table 1                                                         ______________________________________                                                   A        B        C       D                                        Developer  De-      Waste    Electro-                                                                              Re-                                      chemi-     velop    de-      lyzed   vived                                    cals       er       veloper  developer                                                                             developer                                ______________________________________                                        Hydroquinone                                                                             8.0      6.8      7.5     8.0                                      (g/l)                                                                         1-Phenyl-3-                                                                   pyrazolidone                                                                             0.24     0.22     0.23    0.24                                     (g/l)                                                                         Anhydrous sodium                                                                         85.0     73.0     82.0    85.0                                     sulfite (g/l)                                                                 Boraz (g/l)                                                                              1.00     0.97     0.98    1.00                                     Bromine ion (as                                                               potassium bro-                                                                           1.0      2.0      1.0     1.0                                      mide) (g/l)                                                                   pH         8.50     8.45     8.80    8.50                                     ______________________________________                                    

The electric power required for the above electrolysis was 0.025 KWH perliter of the electrolyzed developer.

EXAMPLE 2

A color developer having the composition and color described in column Aof Table 2 was fed into a developing chamber of a silver halide colorphotographic film processor, and a color print film was developed. Thewaste color developer (column B of Table 2) discharged from thedeveloping chamber was charged into cathode compartment 5 of anelectrolytic cell including an ion exchange membrane such as shown inFIG. 1 in which a stainless steel cathode was separated from a platinumanode by a strong base type anion exchange membrane, and a 0.5 N aqueoussolution of sodium sulfate was charged into anode compartment.Electrolysis was performed while maintaining the current density of theanion exchange membrane at 5 mA/cm². The composition and color of theelectrolyzed developer that flowed from the cathode compartment 5 wereas shown in column C of Table 2.

2-Amino-5-diethyl aminotoluene hydrochloride, anhydrous sodium sulfite,sodium carbonate monohydrate, potassium bromide and sulfuric acid (forpH adjustment) were added to the electrolyzed developer C to formrevived color developer (column D of Table 2).

A color print film was developed under the same conditions as in thecase of the color developer A using the revived developer. Thephotographic characteristics of the developed color image were the sameas in the case of the color developer A.

                  Table 2                                                         ______________________________________                                        De-         A       B        C        D                                       velop-      Color   Waste    Electrolyzed                                                                           Revived                                 er          de-     color    color    color                                   chemi-      velop-  develop- develop- develop-                                cals        er      er       er       er                                      ______________________________________                                        2-Amino-5-diethyl                                                             aminotoluene                                                                  hydrochloride                                                                             6.8     3.0      3.3      6.8                                     hydrochloride                                                                 (g/l)                                                                         Anhydrous sodium                                                              sulfite (g/l)                                                                             5.7     4.0      5.0      5.7                                     Sodium carbonate                                                                          22.0    20.0     21.0     22.0                                    monohydrate (g/l)                                                             Bromine ions                                                                  (calculated as                                                                potassium bromide)                                                                         1.7    2.2      1.7      1.7                                     (g/l)                                                                         pH          11.08   10.65    11.20    11.08                                   Color       pale    red-     pale     pale                                                yellow  brown    yellow   yellow                                  ______________________________________                                    

The electric power required for the above electrolysis was 0.020 KWH perliter of the electrolyzed color developer.

EXAMPLE 3

A color developer having the composition shown in column A of Table 3was supplied to a developing chamber of a color paper processor todevelop the color paper. The waste color developer (having thecomposition shown in column B of Table 3) discharged from the developingchamber of the processor was charged into a cathode compartment 16 anddeionation compartments 18 of an electrodialytic cell of the type shownin Table 2 in which a stainless steel cathode was separated from agraphite anode by five strong base type anion exchange membranes andfive strong acid type cation exchange membranes disposed alternately,and a 0.3N aqueous solution of sodium sulfate was charged intoenionation compartments 19 and an anode compartment 17. A direct currentwas passed between the cathode and the anode so that the current densityof the anion and cation exchange membranes became 3 mA/cm².

When the above electrolysis proceeded to some extent, the effluent 24from the cathode 16 was charged into the deionation compartments 18 andthe electrolysis was continued. The waste developer which had so farflowed out from the deionation compartments was charged into the cathodecompartment 16.

When the electrolysis took the stationary state, the compositions of theeffluent from the cathode compartment 16 and the effluent from thedeionation compartments 18 were as shown in columns C and D of Table 3.Hydroxyethyl ethyl para-phenylenediamine sulfate, anhydrous sodiumsulfite, potassium carbonate, potassium bromide and sulfuric acid (forpH adjustment) were added to the effluent D from the deionationcompartments to form a revived color developer (having the compositionshown in column E of Table 3). A color paper was developed with therevived developer under the same conditions as in the case of the abovecolor developer A. The properties of the color photograph obtained werethe same as in the case of the color developer A.

                                      Table 3                                     __________________________________________________________________________               A    B    C    D    E                                                              Waste                                                                              Effluent                                                                           Effluent                                                                           Revived                                        De-             color                                                                              from the                                                                           from the                                                                           color                                          velop-     Color                                                                              de-  cathode                                                                            deiona-                                                                            de-                                            er         de-  vel- com- tion vel-                                           chemi-     velop-                                                                             op-  part-                                                                              compart-                                                                           op-                                            cals       er   er   ment ments                                                                              er                                             __________________________________________________________________________    Hydroxyethyl ethyl                                                            p-phenylenediamine                                                                       7.5  6.0  6.3  6.3  7.5                                            sulfate (g/l)                                                                 Anhydrous sodium                                                                         4.5  4.0  4.2  4.1  4.5                                            sulfite (g/l)                                                                 Potassium carbonate                                                                      100.0                                                                              99.0 99.5 99.0 100.0                                          (g/l)                                                                         Bromine ion (g/l,                                                             calculated as                                                                            0.2  1.0  0.8  0.1  0.2                                            potassium bromide)                                                            pH         10.8 10.7 11.0 11.0 10.8                                           __________________________________________________________________________

The electric power required for the above regeneration treatment was0.030 KWH per liter of the waste color developer.

EXAMPLE 4

A developer having the composition shown in column A of Table 4 was fedinto a developing chamber of a black-and-white film processor, and ablack-and-white silver halide photographic film was developed. The wastedeveloper (having the composition shown in column B of Table 4)discharged from the developing chamber was charged into a cathodecompartment 5 of an electrolytic cell of the type shown in FIG. 1 inwhich a stainless steel cathode was separated from a platinum-platedtitanium anode by a strong base type anion exchange membrane havingpermselectivity for monovalent anions, and a 0.5N aqueous solution ofsodium sulfate was charged into anode compartments 6. Electrolysis wascarried out while maintaining the current density of the anion exchangemembranes 4 at 5 mA/cm².

The electrolyzed developer (having the composition shown in column C ofTable 4) that flowed out from the cathode compartment 5 was charged intodeionation compartments 18 of an electrodialytic cell of the type shownin FIG. 2 in which a stainless steel cathode was separated from agraphite anode by five strong base type anion exchange membranes havingpermselectivity for monovalent anions and five strong acid type cationexchange membranes having perselectivity for monovalent cations arrangedalternately, and a 0.5N aqueous solution of sodium sulfate was chargedinto a cathode compartment 16, enionation compartments 19 and an anodecompartment 17. Electrodialysis was carried out while maintaining thecurrent density of each of the ion exchange membranes at 5 mA/cm². Thecomposition of the dialyzed developer that flowed out of the deionationcompartments 18 was as shown in column D of Table 4.

Hydroquinone, methyl para-aminophenol sulfate, anhydrous sodium sulfite,sodium carbonate and sulfuric acid (for pH adjustment) were added to thedialyzed developer D to form a revived developer (having the compositionshown in column E of Table 4). A black-and-white silver halidephotographic film was developed with the revived developer under thesame conditions as in the case of the developer A. The characteristicsof the photograph obtained were the same as in the case of the developerA.

                                      Table 4                                     __________________________________________________________________________    De-       A    B    C     D     E                                             velop-    De-  Waste                                                                              Electro-                                                                            Electro-                                                                            Revived                                       er chem-  velop-                                                                             develop-                                                                           lyzed dialyzed                                                                            develop-                                      icals     er   er   developer                                                                           developer                                                                           er                                            __________________________________________________________________________    Hydroquinone (g/l)                                                                      12.0 9.0 10.5   10.3  12.0                                          Methyl p-amino-                                                               phenol sulfate                                                                          3.0  2.5 2.8    2.7   3.0                                           (g/l)                                                                         Anhydrous sodium                                                                        67.5 60.0                                                                              65.0   64.0  67.5                                          sulfite (g/l)                                                                 Sodium carbonate                                                                        68.5 67.5                                                                              68.0   68.0  68.5                                          (g/l)                                                                         Bromine ions (g/l,                                                            calculated as                                                                           0.2  1.5 1.3    0.2   0.2                                           potassium bromide)                                                            pH        10.5 10.4                                                                              11.0   11.0  10.5                                          __________________________________________________________________________

The electric power required for the above regeneration treatment was0.020 KWH per liter of the waste developer.

EXAMPLE 5

A color developer having the composition shown in column A of Table 5was fed into a color developing chamber of a color film processor, and acolor negative film was developed. The waste color developer dischargedfrom the developing chamber (having the composition shown in column B ofTable 5) was charged into a cathode compartment of an electrolytic cellin which a nickel cathode was separated from a graphite anode by astrong acid type cation exchange membrane. and a 0.5N aqueous solutionof sulfuric acid was charged into an anode compartment. Electrolysis wascarried out while maintaining the current density of the cation exchangemembrane at 4 mA/cm².

The electrolyzed color developer (having the composition shown in columnC of Table (5) that flowed out from the cathode compartment of the aboveelectrolytic cell was charged into deionation compartments 18 of anelectrodialytic cell of the type shown in FIG. 2 in which a stainlesssteel cathode was separated from a graphite anode by five strong basetype anion exchange membranes and five strong acid type cation exchangemembranes disposed alternately, and a 0.5N aqueous solution of sodiumsulfate was charged into a cathode compartment 16, enionationcompartments 19 and an anode compartment 17. Electrodialysis wasperformed while maintaining the current density of each of the ionexchange membranes at 5 mA/cm². The composition of the dialyzed colordeveloper that flowed from the deionation compartments 18 was as shownin column D of Table 5.

4-Amino-N-ethyl-N-(β-methanesulfonamide ethyl)m-toluidine sesquisulfatemonohydrate, anhydrous sodium sulfite, sodium hydroxide and sodiumcarbonate were added to the resulting dialyzed color developer D to forma revived color developer having the composition shown in column E ofTable 5. A color negative film was developed with the revived colordeveloper under the same conditions as in the case of the colordeveloper A. The characteristics of the developed color photograph werethe same as in the case of the color developer A.

                                      Table 5                                     __________________________________________________________________________              A     B    C     D    E                                             Devel-    Color de-                                                                           Waste                                                                              Electro-                                                                            Dialyzed                                                                           Revived                                       oper      vel-  color                                                                              lyzed color                                                                              color                                         chemi-    op-   develop-                                                                           color develop-                                                                           develop-                                      cals      er    er   developer                                                                           er   er                                            __________________________________________________________________________    4-Amino-N-ethyl-N-                                                            (β-methanesulfon-                                                        amide ethyl)-m-                                                               toluidine sesqui-                                                             sulfate mono-                                                                 hydrate (g/l)                                                                           7.0   5.0  5.2   5.2  7.0                                           Anhydrous sodium                                                              sulfite (g/l)                                                                           2.3   2.0  2.2   2.1  2.3                                           Sodium hydroxide                                                              (g/l)     0.85  0.55 0.54  0.53 0.85                                          Sodium carbonate                                                              monohydrate (g/l)                                                                       50.8  50.0 50.0  49.8 50.0                                          Bromine ions (g/l,                                                            calculated as                                                                 potassium bromide)                                                                      0.50  1.20 1.20  0.50 0.50                                          pH        10.80 10.75                                                                              10.75 10.75                                                                              10.80                                         __________________________________________________________________________

The electric power required for the above-mentioned regeneration was0.030 KWH per liter of the waste color developer.

EXAMPLE 6

Using a developer having the composition shown in column A of Table 6, ablack-and-white film was developed. The waste developer having thecomposition shown in column B of Table 6 was charged into a cathodecompartment 5 of an electrolytic cell of the type shown in FIG. 1 inwhich a stainless steel cathode was separated from a graphite anode by astrong base type anion exchange membrane, and a 0.5N aqueous solution(column A of Table 7) of sodium sulface was charged into an anodecompartment 6. Electrolysis was performed while maintaining the currentdensity of the anion exchange membrane at 5 mA/cm². When theelectrolysis was performed for 5 hours, the composition of the catholytesolution (the electrolyzed developer) changed as shown in column C ofTable 6. The components of the anolyte solution changed as shown incolumn B of Table 7.

An aqueous solution of sodium hypochlorite (available chlorine 10%)containing 5 grams of available chlorine per gram of COD of the effluentfrom the anode compartment (having the composition shown in column B ofTable 7) was added dropwise to the effluent from the anode compartment,and the mixture was stirred. It was then neutralized with an aqueoussolution of sodium hydroxide. The COD of the effluent from the anodecompartment was decreased drastically as shown in column C of Table 7.

                  Table 6                                                         ______________________________________                                                     A      B          C                                                           De-    Waste deve-                                                                              Electro-                                                    velop- lop-       lyzed                                                       er     er         developer                                      ______________________________________                                        Hydroquinone (g/l)                                                                           8.0      6.5        7.5                                        Methyl p-aminophenol                                                                         2.0      1.8        1.9                                        sulfate (g/l)                                                                 Anhydrous sodium sulfite                                                                     90       85         88                                         (g/l)                                                                         Sodium carbonate mono-                                                                       52.5     52.0       52.2                                       hydrate (g/l)                                                                 Potassium bromide (g/l)                                                                      5.0      6.5        2.0                                        COD (ppm)      25,000   25,000     25,000                                     ______________________________________                                    

                  Table 7                                                         ______________________________________                                                  A        B          C                                                                  Effluent   Effluent                                                           from the   shown in                                                  Anolyte  anode      column B                                                  solu-    compart-   after being                                               tion     ment       treated                                         ______________________________________                                        Sodium sulfate                                                                            35          40        40                                          (g/l)                                                                         COD (ppm)    0         200         1                                          ______________________________________                                    

EXAMPLE 7

A color film was developed using a part of a color developer having thecomposition shown in column A of Table 8. The remaining color developerwas divided into two portions. One portion was stored for 60 days in apolyethylene container. The other was charged into a cathode compartmentof an electrolytic cell in which a stainless steel cathode was separatedfrom a platinum-plated titanium anode by a strong acid type cationexchange membrane, and a 0.5N aqueous solution of sulfuric acid wascharged into an anode compartment. While passing a direct current of 200mA between the cathode and the anode, it was stored for 60 days. Thecompositions of the color developer portions after storage in thismanner were as shown in columns B and C of Table 8. When a color filmwas developed with each of the color developers B and C under the sameconditions as in the case of the color developer A, the samephotographic characteristics as in the case of the color developer Awere obtained in the case of the color developer C. But in the case ofthe color developer B, the photographic characteristics obtained weredifferent from those obtained in the case of the color developer A.

                  Table 8                                                         ______________________________________                                                    A        B           C                                                        At       After storage                                                                             After storage                                            the      for 60 days for 60 days                                  Color       start    in a poly-  by the method                                developer   of       ethylene    of this in-                                  chemicals   storage  container   vention                                      ______________________________________                                        4-Amino-N-ethyl-N-                                                            (β-methanesulfon-                                                         amide                                                                        ethyl) m-toluidine                                                                        5.0      4.0         5.0                                          sesquisulfate                                                                 monohydrate (g/l)                                                             Anhydrous sodium                                                                          2.0      1.7         2.0                                          sulfite (g/l)                                                                 Sodium carbonate                                                                          50.0     51.0        50.0                                         monohydrate (g/l)                                                             Sodium hydroxide                                                                          0.55     0.57        0.55                                         (g/l)                                                                         Potassium bromide                                                                         1.0      1.0         1.0                                          (g/l)                                                                         pH          10.75    10.95       10.75                                        ______________________________________                                    

I claim:
 1. A method for regenerating a waste developer left after processing silver halide photographic materials, which comprises electrolyzing the waste developer using an electrodialytic cell comprising a cathode, an anode and alternating anion exchange membranes and cation exchange membranes arranged therebetween to define a cathode compartment adjacent the anion exchange membrane at one terminal of the cell, a plurality of intermediate enionation and deionation compartments with a set of the deionation compartments alternately disposed between a set of the enionation compartments, and an anode compartment adjacent the cation exchange membrane at the other terminal of the cell; the electrolysis being effected while passing the waste developer through the cathode compartment and charging the effluent from the cathode compartment into the deionation compartments.
 2. A method for regenerating a waste developer left after processing silver halide photographic materials, which comprises first electrolyzing the waste developer by passing it through a cathode compartment of an electrolytic cell comprising a cathode, an anode, and an anion exchange membrane disposed therebetween to define the cathode compartment and an anode compartment; and then electrolyzing the effluent from the cathode compartment of the electrolytic cell by passng it through deionation compartments of an electrodialytic cell comprising a cathode, an anode and alternating anion exchange membranes and cation exchange membranes arranged therebetween to define a cathode compartment adjacent the anion exchange membrane at one terminal of the cell, a plurality of intermediate enionation and deionation compartment with a set of the deionation compartments alternately disposed between a set of the enionation compartments, and an anode compartment adjacent the cation exchange membrane at the other terminal of the cell.
 3. A method for regenerating a waste developer left after processing silver halide photograhic materials, which comprises first electrolyzing the waste developer by passing it through a cathode compartment of an electrolytic cell comprising a cathode, an anode, and a cation exchange membrane disposed therebetween to define the cathode compartment and an anode compartment; and then electrolyzing the effluent from the cathode compartment of the electrolytic cell by passing it through dionation compartments of an electrodialytic cell comprising a cathode, an anode and alternating anion exchange membranes and cation exchange membranes arranged therebetween to define a cathode compartment adjacent the anion exchange membrane at one terminal of the cell, a plurality of intermediate enionation and deionation compartments with a set of the deionation compartments alternately disposed between a set of the enionation compartments, and an anode compartment adjacent the cation exchange membrane at the other terminal of the cell. 